Air duct cleaning and duct repair

When duct cleaning is worth paying for

The EPA's guidance is plainer than most of the ads. Duct cleaning has never been shown to actually prevent health problems. The EPA says to consider it when:

• There is substantial visible mold growth inside the ducts or on other parts of the system.
• Vermin (rodents or insects) are in the ducts.
• The ducts are clogged with so much dust and debris that it blows out of the supply registers.

Outside those cases, I'd spend the money on a new filter, a clean coil and a working drain first. A dirty system is more often a filter problem than a duct problem.

Old ductwork in Fort Walton Beach

Fort Walton Beach has the oldest housing in the metro. Census figures put about 45% of its homes as built before 1980, against 19% in the Crestview ZIPs, where 51% went up in 2000 or later. A house from the 1960s or 1970s near Eglin Parkway or along the Sound may have had three or four air conditioners over the years and still be on its original ducts. Duct board seams dry out, old flex duct sags and tears, and insulation breaks down in an attic that bakes all summer.

In a house that old, cleaning is often the wrong question. If the ducts are crushed or moldy, pricing a duct replacement may make more sense than paying to clean them.

The coupon that turns into a mold quote

A pattern people commonly describe in Florida AC threads: a low-priced whole-house duct cleaning coupon, a technician who finds "mold" once inside, and a quote several times the coupon price for treatment. Sometimes the mold is real. It's humid here, and a system with a clogged drain or a wet air handler closet can grow it. You should see it before you pay for it.

• The EPA says to ask the company to show you any mold they claim to have found. A photo of the inside of your own duct, not a stock image.
• The EPA does not certify duct cleaning companies, so a "certified by EPA" claim is not real.
• The EPA notes that no biocide is registered for use on fiberglass duct materials. Ask what product they plan to use and what it is registered for.
• Get estimates from more than one company, which the EPA also recommends.

Mold on the ducts usually has a moisture cause upstream. Clean it and leave the cause, and it comes back. See musty smells and humidity; a clogged drain line is near the top of the list.

New AC, same old ducts

A frequent question: the house got a new system last year and it is still dusty, so should the ducts be cleaned? A replacement usually reuses the existing ductwork, which may be as old as the house. And most household dust is not coming out of the ducts at all. Check that the filter fits its slot with no gaps, then ask whether the return side is pulling attic dust through a torn joint. A very restrictive filter isn't the fix either; it can choke airflow.

Leaky attic ducts and storm damage

Most houses here run ducts through the attic. In August that attic is far hotter than the outdoor high, which averages 93°F at Bob Sikes Airport. A torn flex duct or a supply joint that pulled loose dumps cooled air into that space and pulls hot, wet attic air back in on the return side. Signs:

• One or two rooms that never cool while the rest of the house does.
• Weak airflow at registers far from the air handler.
• Higher bills with no change in how you set the thermostat.
• Insulation dust around return grilles.

The DOE's Energy Saver guide lists sealing ducts as one of the basic ways to cut cooling costs. Repairs range from resealing joints with mastic to replacing crushed or rotted runs.

Hurricane Isaias brought 11.20 inches near Fort Walton Beach and 11.65 inches near Mary Esther. If wind opened the roof and the attic got wet, wet duct insulation should be inspected and usually replaced, not cleaned. Our after the hurricane page covers the rest of the system. Whether duct work needs a permit depends on the scope and on which building department covers your address. Okaloosa County and Walton County each run one. Crestview and Fort Walton Beach have their own, as do Destin and Niceville. Ask the company, and confirm with that office.

What it costs

Service	Published range	Source
Air duct cleaning	$300 to $700, $500 average	Fixr
Typical AC repair, for comparison	$250 to $700, $375 average	Fixr

National figures, not a local average and not our quote.

Duct repair is priced by what is found, so get it in writing after the technician has been in the attic. Ask whether the price includes sealing the air handler cabinet and the return plenum, since those leak as often as the ducts do.